Scientists have come up with a way to 'print' lasers that could one day be used to create wafer-thin televisions and lighting panels.

Lasers, highly concentrated beams of light, have been used for many applications from fibre optics to reading compact discs since their invention in 1960. But conventional lasers are expensive and don't lend themselves to printed technologies.

Researchers from CSIRO, the University of Melbourne and the University of Padua in Italy have overcome that hurdle by creating affordable tiny, printable lasers using a technology based on 'quantum dots' - nano-sized crystals of semiconducting material.

The researchers suspend these nanocrystals in liquid to create 'inks' which they then printed onto a glass-like material with nanoscale grooves in it.

When light is shone onto the material, it is bounced around inside the grooves and builds up in intensity, exciting the electrons in the quantum dots to a higher energy level and causing them to give off their own light. The colour of the light depends on the size of the nanoparticle.

"If we printed our lasers on a sheet of paper then every single point on that paper would be its own individual laser. It's a flat panel laser," says Dr Jacek Jasieniak, a nanotechnologist with CSIRO, who has been chosen as one of this year's Fresh Science winners.

TVs and solar panels

The technology could be used to create flat coloured lighting panels, or television displays, where each pixel is an individual laser.

"What we want is to eventually be able to replace white light sources in conventional televisions with individual laser pixels that emit light," he adds.

The 'Holy Grail' for this work, says Jasieniak, is to create lasers that are driven by electricity rather than light.

Researchers in Canada have used a similar method to paint quantum dots onto thin glass tubes and produce infrared lasers. Jasieniak says that producing visible lasers, as his team has done, is much more difficult.

He adds that the ability to print quantum dots could have other applications. For example, Jasieniak and his colleagues are also working on making solar cells using a different type of quantum dot.

"The whole idea of taking quantum dots and developing appropriate inks to print different devices is a big thing for the future. We could completely revolutionise printing processes to develop next-generation technologies."